Partitionable portable flexible disk pack

ABSTRACT

Improved flexible disk storage media comprising a pack of flexible recording disks adapted for compact stacking in superposed registration. Each disk is hole-encoded to permit associated disk partitioning apparatus to provide automatic selective partitioning of the pack for selecting a desired disk for the performance of a recording and/or reproducing operation with respect to a surface thereof. Each multiple disk pack is removably contained in a protective jacket during partitioning and transducing operations. The jacket cooperates with automatic jacket-opening means so as to provide for convenient insertion and withdrawal of a disk pack while permitting selective partitioning of the pack while contained in the jacket for the performance of a transducing operation on a selected disk in the pack.

CROSS REFERENCE TO RELATED APPLICATIONS

The following commonly assigned, concurrently filed patent applicationsare related to the subject matter of this application: Ser. No.: 711,579Filed: Aug. 4, 1976; Ser. No.: 711,628 Filed: Aug. 4, 1976; Ser. No.:720,905 Filed: Sept. 7, 1976; Ser. No.: 720,910 Filed: Sept. 7, 1976.

BACKGROUND AND FEATURES OF THE INVENTION

This invention relates to data recording and in particular to a novelimproved multi-disk arrangement for data recording.

Workers in the art of generating and/or utilizing magnetic recordingmedia are aware of the various forms it takes; in the case of digitalrecording these forms have historically comprised drums, disks and tapein various configurations. Each medium has its own advantages andshortcomings depending upon the application. For instance, magnetic drumrecords facilitate relatively good data compression (high data density)and fast access time; however, they are relatively expensive to provideand are not generally suitable for "archival" storage of data. Magnetictape, on the other hand, is comparatively inexpensive and is highlysuitable for "archival" storage; however, it must be accessed serially(not randomly) and relatively slowly.

Magnetic disk storage is intermediate in access speed, facilitatesrandom access and, in many cases, is particularly well suited forstorage of "open-ended" data field (i.e., of indeterminate length).Disks -- especially "flexible disks" -- can serve as a "unit record"medium that is compact, light, and is readily transported, stored, andhandled, interchangeably with other like disks. Accordingly, magneticdisk media are now finding widespread favor, especially in the dataprocessing arts and are currently manufactured and used in great volumeand in several forms. With todays high-volume disk usage, any reductionin disk cost looms highly significant, as workers in the art know. Thisinvention facilitates high-volume/low-cost disk usage, teaching a novelmulti-disk organization, allowing a pack of disks to be handled as asingle record unit.

Recently a step toward cost reduction appeared in the form of theflexible, or "floppy", magnetic disk. Floppy disks can be fashioned fromthe same polyester sheet material as magnetic tape (e.g., the familiarpolyethylene terephthalate), with a magnetic coating thereon -- thisplastic being simply cut into the shape of a circular disk with acentral mounting hole to accommodate the familiar drive-spindle. Such a"prior art" floppy disk is well known to workers and is shown in FIG. 1;a conventional envelope, or jacket, therefor is illustrated in FIG. 2.

The present invention is directed toward improving the design of suchflexible magnetic disks as adapted for collection into a ("floppy")pack, -- something new in the art -- with any disk surface thereof beingadapted for selection, and the pack accordingly "partitioned" or split,by automatic means. That is, with such a "floppy disk pack", theinvention is particularly adapted to facilitate automatic partitioningof the pack to expose any selected disk surface for Read/Writeoperations -- using surprisingly simple means and methods as describedhereinafter.

Workers will recognize that there are many advantageous uses for such"floppy disk packs", for instance, they offer enhanced volumetriceffeciency of data storage -- that is, a maximal number of data bits maybe stored in a given volume with a floppy disk pack, the disks being sothin (e.g., on the order of a few mils thickness) and so compliant as topack closely together. --prior efforts with flexible disks:

Workers have suggested that in certain instances, disks may be assembledinto a flexible multi-disk file, with one or both sides treated torecord data bits in the form of magnetic signals as is well known in theart. One problem, however, has been the preconception that one musthouse such flexible disk packs in a rigid containment structure. Also nosimple, practical way has yet been found to access an individualselected recording surface in a precise, rapid and repeatable manner --principally because these "floppy" substrates are so difficult tostabilize mechanically. Now, workers well know that it is no easy taskto precisely position a Read/Write head between two tissue-thin floppydisks separated by only a few mils, and to do so quickly and simply.And, with such a floppy disk file, dimensional instabilities andvariations (e.g., varying thermal effects, manufacturing tolerances) areto be expected, as workers know. Then, even if one is able to hold eachdisk in a pack at a constant reference position relative to the otherdisks, transducer access and positioning is still problematical.

Accordingly, workers have resorted to special means, heretofore, forpackaging and accessing floppy disk recording surfaces. For instance,"floppy" disks were thought to require support, while rotated (forrecording) also, it was assumed they would suffer undue surface wearfrom frictional effects when stacked contiguously. Accordingly, workershave avoided stacking them directly in contact, i.e.,"one-upon-another". Also, getting head-access to superposed floppy diskshas seemed an impossible task. This invention is adapted to facilitatesuch contiguous stacking without compromising either disk integrity oraccess convenience. --prior art "floppy-disk" handling:

One approach, shown in U.S. Pat. Nos. 3,509,533 to Krijnan and 3,618,055to Van Acker, involved an enclosed pneumatically pressurized chamber,with the flexible disks being stacked in spaced relation on a commonspindle. These disks were perforated with holes to facilitate "pumping"of air through the stack and the associated spindle was "slotted" andadapted to control air flow from the center, radially outward, andthereby facilitate disk manipulation.

With recording density being an inverse function of head/disk spacing,many arrangements have been suggested to facilitate the close"following" of the disk surface by a transducer head. In an earlyapproach (see U.S. Pat. No. 2,950,353 to Fomenko), the air flow wasmanipulated to facilitate transducer/disk engagement at high speed forhigh density magnetic recording. Similar arrangements with pliantflexible disks are disclosed in U.S. Pat. Nos. 3,153,241; 3,225,338;3,369,227 and 3,573,771 also certain flexible disk designs are indicatedin U.S. Pat. Nos. 3,678,481 and 3,668,658; while various forms of aflexible disk file are indicated in U.S. Pat. Nos. 3,867,723; 3,810,243;3,852,820 and 3,838,462.

Workers are also familiar with various means for accessing multi-diskfiles by means for displacing the (otherwise-inaccessible) facingrecording surfaces while the disk stack is rotating, to provideclearance for entry and manipulation of a transducer assembly. Forinstance, a "sliding-transfer" arrangement is disclosed in U.S. Pat. No.3,130,393 to Gutterman (who employs pressurized air to "slide" the disksapart) and in U.S. Pat. No. 2,960,340 to Seidel (phonograph records slidrelative to one another by probe means). But, as workers realize afloppy disk file responds poorly to the "forced-piston" motioncontemplated by the Gutterman arrangement. --problems addressed:

Thus, certain problems come to mind when one contemplates manipulating afloppy disk file. For instance, they have not proven as reliable ordurable as desired; the thin pliable disk can be somewhat fragile,especially when subjected to extreme physical hazards, such as slidingcontact or impact with a sharp-edge like a "separator knife" or atransducer access arm. While the cost of the disk is relativelyinconsequential, the data stored thereon is often invaluable and couldbe defaced by such contact. The present invention is designed toalleviate or eliminate the risk of such destructive contact, andparticularly to teach the partitioning of a disk pack without employing"penetrator knives" as heretofore proposed.

Also, with the increased popularity and use of floppy disk media, it hasbecome especially important to emphasize disk pack features like ready"removability" and record "interchangeability", as well as increased bitdensity and cost effectiveness (e.g., increasing data density per cm²and data capacity per disk spindle, increase in data rate, reduction inaccess motion and rotational delay, improved data reliability and lowercost per M-byte). Indeed the desire for unit record removability has ledto much of the increased use of (single) flexible disks -- e.g.,cartridges with a disk packaged in a jacket like that indicated in FIG.2. Now, such "removable media" can offer many advantages to the user --for instance, the ability to exchange data-set libraries betweenapplications, the availability of data-set backup and security, and theinterchange of data records among alternate drives and systems. Thelightweight, compactness of floppy disks even allow these records to beconveniently mailed between stations, using ordinary postal service.This invention enhances these advantages while also vastly increasingthe data capacity of a disk cartridge.

Data removability, is, however, not without its price -- e.g., the costof disk-loading hardware, of disk packaging (cartridge) means forprotection against contamination and for security and the cost of of thehead-carriage retraction mechanism and control electronics involved, andespecially of the means for aligning Read/Write heads with a selecteddisk track. Such "trade-off" considerations can deter use of removabledisk records -- but with the invention this is not likely to be so. Thatis, the present invention is directed toward providing improvedmulti-disk records, and disk packs, adapted to meet the foregoingproblems and objectives in a manner satisfying minimum-cost objectives.The invention maintains the convenience of the removable floppy disk,while packaging a number thereof in a relatively convenient unit recordfile.

The foregoing and other features, objects and advantages according tothe present invention will be more fully appreciated and become moreapparent upon consideration of the following description of preferredembodiments, taken in conjunction with the attached drawings, whereinlike reference indicia denote like elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are schematic plan views of a prior art flexible disk andan associated prior art jacket, respectively;

FIG. 3 is a diagrammatic plan view of a flexible disk modified with ahole-encoding pattern according to the invention, while

FIGS. 3A, 3B, 3C and 3D are like views of alternate arrays of holes(apertures);

FIG. 4 is a schematic diagram of a flexible disk pack embodimentaccording to the invention, with exemplary disks therein shownexploded-away for illustrative purposes;

FIG. 5 is a schematic side perspective of the disk pack embodiment ofFIG. 4 inter-acting with associated pack-partitioning means; while

FIG. 6 indicates a side view of such an arrangement in operativerelation combination with a turntable and an associated transducercarriage assembly; and

FIG. 5A shows a similar, schematic, view of a like disk pack embodiment,including separator disks as well, with several elements exploded-awayfor illustration purposes;

FIG. 7 is a plan view of an improved protective jacket, especiallyadapted for disk packs like those in FIGS. 4 and 5, while

FIG. 8 shows this jacket in inverted perspective view and disposed inillustrative operative relation with schematically indicated openingmeans and partitioning means;

FIG. 9 is a front perspective view of a "disk drive" adapted forhandling disk pack media like the embodiment of FIGS. 4 and 5, as housedin a protective jacket like that in FIGS. 7 and 8, while

FIG. 10 is an enlarged close-up view of working elements of this drive,with certain superstructure broken-away for clarity of illustration;

FIG. 11 is a schematic side view of a pack partitioning arrangementadapted for use with disk packs like those in FIGS. 4, 5 andparticularly adapted for inclusion in a flexible disk drive like that ofFIGS. 9 and 10; while

FIG. 12 is a similar view of an automatic jacket opening means likewiseadapted for such a disk pack and suited for incorporation in such adrive; and

FIG. 14 is a schematic perspective view of a pair of mating disk-formingdies adapted to form hole-encoded disks of the type indicated in FIG. 3,these dies being shown in schematic operative relation in the side viewof FIG. 13.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS --Flexible disks, ingeneral

FIG. 3 schematically illustrates a preferred embodiment 1 of a flexible(pliant or "floppy" type) disk record adapted, according to theinvention, to be stacked with other like record disks, into a pack asindicated at disk file or stack S in FIGS. 4 and 5. These disks are, asa group and according to the invention, encoded and arranged to bemanipulated as a group for the selectable partitioning, or splitting, ofthe stack adjacent any selected disk surface. This is basicallyaccomplished in accordance with the invention by providing the stackeddisks with an encoded arrangement of apertures such that a plurality ofunique unobstructed paths are provided from at least one end of thestack respectively terminating at the surfaces of successive disks. Athrusting force applied along a selected one of these unobstructed pathswill then cause the stack to be flexed open between a corresponding pairof adjacent disks in the stack. In the preferred embodiments consideredherein, this is controlled according to the circumferential positionassumed by the pack relative to an associated disk engaging means asdescribed hereinafter.

It is instructive to first consider the design and construction of arelatively conventional floppy disk design 1' as indicated in the priorart FIG. 1. Thus, prior art disk 1' may be understood as a well known"industry-compatible" type of flexible disk particularly adapted foremployment as a unit magnetic data record. Such a disk record will berecognized as comprising a circular flexible substrate of polyethyleneterephthalate or the like having a magnetic coating on at least one sideto thus define a magnetic recording surface. Such disks 1' are adaptedfor protective containment and operation within an envelope, or jacket3' as indicated by prior art jacket 3' in FIG. 2 within which such afloppy disk may be stored, as well as rotated for magneticdata-transcription when inserted into appropriate apparatus.

Thus, disk 1' has a central aperture 1'-h for engaging a conventionalrotary-drive spindle (while contained within jacket 3'), there being aprescribed recording track zone 1'-T defined between respective innerand outer track margins 1'-IT, 1'-OT; also, an "index hole" 1'-Ih isdisposed (within 1'-IT) along a prescribed "reference radius" AS andadapted to establish a "Start Radius" for the circumferential datatracks as known in the art. Within inner non-recording margin 1'-IT isan inner "contact annulus" defining the locus of engagement withspindle-contact means as known in the art.

--Locator-hole array:

According to a first feature of novelty, a file of novel flexible disksD-1, D-2, D-3, etc., generally like disk 1, are manufactured as a groupand adapted to include a prescribed array of separating apertures, orlocator holes, L-H, as schematically indicated, for example, by locatorholes L-1, L-2, L-3, etc., in FIGS. 3 and 4. This aperture array will beseen as establishing a certain mode whereby the stacked disks may bepartitioned according to a unique, simple control involving merelyrotating the stack to different (rotational) angular positions, eachposition corresponding to exposure of a respective one of the disks.Each disk in a file, or stack, S will be understood as having a uniqueidentifiable number of such locator holes L-H so that when the disks aresuperposed with their index holes 1-Ih and their circumferential edgesin registry, they will be seen to represent a hole-encoded array. Thatis, when viewed from one side, the stack will present an array oflocator holes L-H in registry at different circumferential angularlocations about the disk periphery that terminate at successive disks.Thus, each locator hole corresponds to a prescribed select-plunger siteadapted to facilitate the splitting, (i.e., partial-partitioning), ofthe stack to expose the recording surface of a corresponding selecteddisk.

Accordingly, locator holes L-1 pass through all disks and correspond tothe "selection" (exposure of upper suface) of the top disk D-1, holesL-2 correspond to exposure of D-2, terminating at disk D-1 so thatinsertion of a plunger therethrough splits pack S to expose the upperrecording surface of disk D-2 -- or the lower surface of D-1; whileholes L-3 expose D-3; holes L-11 expose disk D-11, and so on. This holepattern is unique for each disk, the holes adding cumulatively in onedirection along the pack axis.

Preferably, locator holes L-H are arranged along a circumferential trackor locator locus L-T and spaced a prescribed constant radial distancefrom the disk center and separated by a prescribed constantcircumferential distance, or angular separation (that is, angulardisplacement φ₁₋₂ is the same as φ₂₋₃, etc. in FIG. 3). These encodedlocator holes are thus each centered on a prescribed associated radialaxis, e.g., axis A_(X) -1 for hole L-1, A_(X) -2 for hole L-2, etc., theholes being of prescribed identical size and configuration -- onconfiguration being elliptical holes (or notches, as discussed below).Thus, as better illustrated in associated FIG. 4, for instance, wheneleven (11) such flexible disks 1 are superposed in registry, a stack Sresults, including disks D-1, D-2 through D-11 disposed for co-rotationby a common spindle (not shown here, but well known, and schematicallyindicated by FIG. 6 and described below). The pattern of locator holeswill be such as to provide the mentioned hole-encoding and enable aprescribed mode of partition.

Thus, for instance, the topmost disk D-1 in the stack is arranged tohave a single hole L-1, while the second disk D-2 is arranged to haveone additional locator hole L-2 (besides L-1) disposed along an initialaxis A_(X) -2; the third disk D-3 in the stack in turn arranged to haveidentical locator holes L-1, L-2 (as disk D-2) together with one addedlocator hole L-3 (distinguishing it from D-2, D-1 and all other disks instack S) aligned along axis A_(X) -3 and along circumferential axis L-T,A_(X) -3 being angularly displaced from A_(X) -2 by a prescribedconstant angle. The fourth disk D-4 (not shown) is accordingly likewisecumulatively encoded with locator holes L-1, L-2 and L-3 in registrywith these holes on D-3, together with an added hole L-4 along axisA_(X) -4 uniquely identifying this disk and spaced along track L-T andangularly displaced from axis A_(X) -3 by the same prescribed amountφ₁₋₂ = φ₂₋₃ (for example 18°). Eleventh disk D-11 is similarly encodedaccording to the same pattern, its locator holes L-1 through L-10 beinga duplicate of these of adjacent disk D-10 with hole L-11 being added asindicated, (and likewise for other disks in the pack.) Such aselect-hole-encoding will generate a coordinated stack of flexible diskswhich is arranged so that insertion of a separating plunger at aprescribed angular orientation (e.g., along track L-T, at a selectedangular increment from the "Start Radius" AS) can deflect an appropriatesub-group of disks aside to create the desired stack partition fortransducer access and engagement with the selected, corresponding disksurface, as illustrated in FIGS. 5 and 6.

This operation will be better understood by consideration of FIGS. 5 and6 where stack S is shown engaged upon a turntable TT with the disk hubssuitably engaged (e.g., pressed thereon by spindle clamp SC) againstrotatable spindle hub S-H as known in the art. A plunger, or disk-selectmeans P will be disposed nearby, being located generally along the"cylindrical locus" including locator track L-T such as to beselectively insertable up through track L-T a prescribed excursion --and thereby split pack S for "transducer access" by transducer assembly117 (FIG. 6). Assembly 117 comprises a carriage including arm 11carrying transducer head 15 and threadedly engaged at barrel 118, forlateral translation (into pack S as is well known -- see arrow) byrotation of lead screw 112. Motor 111 is coupled to rotate screw 112 andcontrolled in a known manner to effect this pack-insertion at prescribedtimes. Thus, transducer 15 is generally thrust toward, or away, frompack S as indicated and known in the art so that any given (upper) disksurface may be accessed and operated upon.

Thus, in the illustrated arrangement of FIGS. 5 and 6, the upper surfaceof disk D-3 will be understood as "selected" for access by transducer 15with overlying disks D-1 and D-2 being thrust upwards and away byplunger P as shown. Accordingly, (and understanding the hole-encoding tobe as indicated in FIGS. 3 and 4 above) for selection of D-3, pack Swill be angularly rotated with respect to the "thrust-path" T_(p) ofplunger P to bring P into registry with selected locator hole L-3. Now,when plunger P is actuated to be thrust upward, it will pass throughholes L-3 which are provided in all disks D in the stack S except fordisks D-2 and D-1 (which have no L-3 holes) -- and this will thrust D-2and D-1 upwards (as indicated in FIGS. 5 and 6) to a prescribedpartially-partitioned condition. This will allow entry of access arm 11,and particularly of shroud 13 on the distal end thereof. As furtherdiscussed below, plunger P is later retracted with shroud 13 thenproviding supporting engagement with (the lower surface of) disk D-2during stack rotation. In this way, disks D-1, D-2 may be helddeflected-away while pack S is rotated and head 15 is engaged on D-3 fora transducing operation.

According to a further feature, shroud 13 is arranged to smoothly engagesuch a deflected disk -- bending all deflected disks over head 15 as thepack is rotated (within its jacket); also allowing the assembly 117 tobe thrust a greater or lesser extent into the stack for translatingtransducer 15 between various recording tracks on a selected disk.

Similarly, if disk D-2 is next "selected" for transducer operations,transducer mount 117 will be withdrawn, and the rotation of stack Sinterrupted, with the stack being oriented (as discussed below) to alignlocator hole L-2 (associated with selection of D-2) above plunger P sothat upward thrust of the plunger the same prescribed distance as beforewill pass it through the registering locator holes L-2 in all disksexcept uppermost disk D-1 -- which has no L-2 hole and accordingly willbe thrust into the approximate location of disk D-2 in FIG. 6. This willthen allow the re-introduction of the access arm 11, i.e., of shround 13which will then be engaged with the under-side of D-1, so that, with thesubsequent retraction of plunger P, stack S may again be rotated toinitiate transducer operations upon this selected recording surface(upper face of disk D-2). FIG. 5 indicates, in schematic perspectiveview, the same upward thrusting of disks D-1 and D-2 and splitting ofstack S as indicated in the side sectional view of FIG. 6, with thedisks flexing and bending along a prescribed portion thereof (FL) underthe upward thrust of the plunger.

--Partition method:

It will be evident that such a partitioning mode involves the simplerotation of the pack relative to the plunger, i.e., to an angularorientation which registers a corresponding pack select-site therewith.Workers will perceive various ways of effecting this. Preferably in thisembodiment, for each partition cycle (i.e., associated with exposure ofeach disk), the pack is brought to the reference orientation [i.e.,rotating to align "Start Radius" with the plunger path] and thenadvanced by the number of successive select-sites required to registerthe proper site (i.e., corresponding to the particular disk "selected")with the plunger path -- preferably doing so digitally.

Table I below summarizes preferred exemplary dimensions andcharacteristics of this floppy disk embodiment and associated disk packmentioned above:

                  TABLE I (FIGS. 1-6)                                             ______________________________________                                        Disk material:                                                                          3 mil (nominal) polyethylene terephthalate                                    with burnished magnetic oxide coating                                         (randomly oriented Fe.sub.3 O.sub.2) on both sides.                           Max. coeff. of expansion:                                                     Thermal: 9 × 10.sup.-6 in./in./° F                               Hygroscopic: 11 × 10.sup.-6 in./in./%RH;                      Disk diameter:                                                                          7.88"; recording between 4.06" (track no.                                     "7b") and                                                                     7.23" (track no. "00") radii;                                                 index aperture (1-Ih): 0.100 in diam.;                                        at 1.7-2 inches radially out from disk                                        center.                                                                       "IBM compatible" format [see AN std.                                          document no. 388/75-23 for a flexible                                         cartridge apt for operation at 50-125° F                               temperature and 8-80% relative humidity].                           Locator holes                                                                 (L-H):    spaced on 18° centers, along L-H locus at                              7.5-7.6" diameter and about 0.156" in                                         diameter (for 93 mil plunger rod), with                                       hole spread of about 3.6° .                                  ______________________________________                                    

--Recording characteristics:

With a conventional (ferrite-core) magnetic Read/Write head lightlyloaded against the recording zone of a selected subject disk, mountedatop an opposing contact pad, provided conventionally (e.g., as on theBurroughs No. 2027-1441 Flexible Disk Drive, for example), the recordingand other characteristics will be generally as known in the art exceptwhere otherwise stated.

The described flexible disks may be expected to exhibit verysatisfactory resistance to wear and abrasion as understood in the art(e.g., after about one-million wear revolutions on any one track signalamplitude of an "all double-frequency recording" should have no bitsexhibiting less than about 75% of the initially recorded signalamplitude). The subject disks are best adapted for "soft sector" formaterecording (as opposed to the "hard sector", or perforation-designatedformat, known in the art), the index pulses being generated and sensedwithout resort to more than a single index aperture.

Now, as those skilled in the art will appreciate, improved flexiblerecording disks of the type described will lend themselves to many formsof data recording and especially magnetic recording or optical (e.g.video) recording. For instance, with the familiar array of concentricmagnetic recording tracks, it may be desired to employ a clocking meanssuch as a separately-recorded clock track with its own separatetransducer, or alternatively a separate clock track disk can beincorporated into each pack as known in the art. On the other hand,known techniques may be used which require no separate timing track, forexample, inserting a "parity bit" at predetermined locations along eachdata track or using a recording mode which is "self-clocking".

Various alternate configurations and materials will occur to thoseskilled in the art, such as the use of chromium oxide or like magneticcoating or the use of acetate or like flexible substrate material, orthe arrangement of locator holes in different patterns and/or shapes asdiscussed below.

--Alternate locator-aperture configurations:

The locator holes L-H need not be elliptical but may instead be circularas indicated in FIG. 3-C, (rather then being elongated along the locatoraxis L-T sufficient to accommodate contemplated variations inlocator-rod positioning relative to the disk stack, as is indicated inFIG. 3.) Disk D' in FIG. 3-C is generally the same as the disk 1 in FIG.3, except that the locator holes L-1, L-2, etc. and in FIG. 3 areextended in their elongate direction along axis L-T to be roughly twiceas long, with rounded edges, (preferred: about 0.16 × 0.3 inches) wherethey are circular in FIG. 3-C.

As a further alternative, the locator apertures may comprise "notches"rather than "holes" as indicated in FIG. 3-D for alternate diskembodiment D". Disk D" is generally the same as disk 1 in FIG. 3 exceptthat the locator holes here comprise a pair of rather semi-ellipticaledge notches L"-1 and L"-2. Workers in the art will conceive other likemodifications, for instance, where the entire periphery of the disk is"cut-out" between all locator holes -- such as by cutting out the"lands" between L"-1 and L"-2 in FIG. 3-D. Alternatively, the diskperiphery may be cut-back within the hole peripheries except for"sector-lands" extending radially from the disk, forming extendedcircumferential "tabs" adapted to engage select-rods -- being disposedentirely about the disk except where the locator holes would haveexisted (and between such locator sites as well). Of course, the sizeand configuration of a locator aperture will generally correspond tothat required to accommodate a given partitioning-plunger (shape,diameter) configuration and consistent with the positioning accuracy ofthe associated "select-partitioning" system. Such a "tab-select"arrangement will be better adapted for relatively rigid disks.

--Multiple "partition-plungers"; "paired" locator holes:

Further, according to a modified feature of the invention, indicatedfunctionally in FIG. 3A, a plurality of such "partition-plunger means"(rather than a single plunger) may be used, together with associatedplural sets of accommodating locator-holes. Thus, a modified embodiment101 (identical to disk 1 in FIG. 3 except as otherwise described) willbe seen as including "locator-sectors" characterized by a pair oflocator holes A and B symmetrically flanking each "locator axis" andequidistant therefrom. With such a modified "double-hole" locatorpattern, disk 101 will thus be understood as intended for use with apair of partitioning plunger rods, each similar to that described inconnection with FIGS. 5, 6 and 11, except that two rods (rather thanone) are used to deflect the pack (--such a pair being more fullydescribed below in connection with FIG. 12).

Thus, for instance, rather than a single select hole (e.g., L-1, FIG. 3)being centered in a "first locator sector" along the "first selectorradius", A_(X) -1, the somodified flexible disk embodiment 101 (FIG. 3A)substitutes a pair of such holes (L-1A, L-1B), each displaced from thisaxis A_(X) -1, on opposite sides along locator track L-T, by the sameangle φ (i.e., symmetrically flanking their associated selector radius).Similarly, the second locator sector and its radius A_(X) -2 serve toreference two "select apertures" (rather than one), namely L-2A, L-2B;likewise for the "third" select radius A_(X) -3 about which a pair ofassociated select apertures L-3A, L-3B are symmetrically flanked.

Thus, for example (and as more fully described below), when the flexibledisk (D-4) next to disk 101 assumed to be D-3), in an associated stackis to be "selected" for Read/Write operations, the stack will bepartitioned by the pair of locator rods -- the rods being moved intoregistry with associated locator holes L-4A, L-4B (shown in phantomhere) flanking the "fourth" select radius A_(X) -4. Then, when one rodis thrust upward in the "standard" manner, disk 101 (i.e., D-3) alongwith the first and second in the stack (i.e., D-1, D-2) will be liftedupwardly to expose the upper recording surface of D-4.

--Up/down selection mode, with opposed plunger pairs and "stripping" ofselected disk:

FIG. 3B indicates how a pair of associated select plunger means areadapted to be "opposingly partitioned", i.e., be driven in oppositedirections, so that, to the upward partitioning-thrust there is added asecond contemporaneous downward, partitioning-thrust in each partitionoperation. As workers can see, this added down-thrust can "strip" the"selected" disk from the upwardly-thrust stack portion -- morepositively and more quickly -- and prevent it from being accidentiallycarried-up with it (e.g., adhering via suction or static electricity,etc.). Further, such a "paired-sites/alternate hole" array of locatorholes is provided to accommodate this "opposed partitioning" mode.Modified disk embodiment 201 in FIG. 3B illustrates this schematically(being identical to embodiment 101 in FIG. 3A, except that only one"companion hole" in each pair is cut through -- to thereby accommodateopposing (up-down) plunger action on a sector during "selection". Thus,there are a pair of select-hole "sites" in each sector.) The sites pairsflank their associated select-radius A_(X) in equidistant symmetry;however, with only one hole in each such pair actually cut through atany sector -- i.e. with "up-holes" cut where sector-selection involvesselection of the given disk or a superposed one, and with "down-holes"through all other sectors. This hole-pattern will be seen asaccommodating the "opposed-partitioning" mode described.

Thus, for instance, disk 201 may be viewed as constituting the fourthdisk (from the top) in a stack (much in the manner of embodiment 101 inFIG. 3A), with each of its select radii A_(X) flanked symmetrically by apair of such (up/down) "select sites", (e.g., an upward-select site atL-1U with a hole cut there;, and a downward-select "site" L-1D, with no"hole" cut there -- both these holes-sites being found in the "firstsector", symmetrically flanking the "first" select axis A_(X) -1).

This "paired site/single hole" pattern of locator-holes will beunderstood as functioning to provide each disk in a given stack withone, and only one, select hole cut in each and every one of its "selectsectors". Thus, for any given disk in a given stack, there will be onesuch locator hole (but only one) cut in each sector -- with "up" holescut in the disks own "select sector" (e.g., sector "four" at A_(X) -4for disk D-4) implying up-deflection of superposed disks; and in all the"lower-order" sectors (corresponding to the number of disks "below" thegiven disk, e.g., D-5 through D-20 "below" selected disk D-4); whereas,conversely, "down" holes are cut in all other disks ("higher order") atthis sector. For example, for disk 201, or D-4, in a 20-disk pack,"up-holes" L-1U, L-2U, L-3U and L-4U are cut only for the first foursectors, with "down" holes cut for all other, "higher-order", sectors(i.e., L-5D, L-6D through L-20D). Similarly, the "topmost" disk (D-1)has a "up-hole" cut only at its first sector (adjacent axis A_(X) -1)with all other holes being "down-holes".

Hence, in the selection of the "first" (i.e., top) disk D-1 in a stack,associated with disk 201, the upward thrusting select-plunger will beunderstood to pass through all disks (through "up holes" L-1U in thefirst sector of all disks including D-1), while the downward-thrustingplunger will pass through "no disks", but merely thrust D-1 downwardlyto "pin" it. Or, for the selection of the next (i.e., second) disk, D-2,in this stack, the "up plunger" will be registered at L-2U and will passthrough all disks except D-1 (through all "up" holes in the secondsector of D-2 to D-n), and so deflect D-1 to expose D-2, while the "downplunger" will register at site L-2D and will pass only through disk D-1to "strip away" D-2, pushing it downward. Or, in the selection of thethird disk, D-3, the "up" plunger will pass through disks D-3 to D-20(L-3U holes therein), while the "down" plunger will pass through disksD-1 and D-2 only (L-3D holes therein) -- so on and so fourth.

Now, a "paired" array of locator holes as above described (such as inFIG. 3A) need not, in all cases, imply the symmetry of hole locationdescribed and illustrated (i.e., symmetrical flanking of given selectaxis). But such symmetry is preferred. For instance, it affords anextraordinary, unexpected advantage in event of "double side" recordingwhereby the disk stack may be "flipped" (turned upside-down) and stillbe partitioned with a plunger pair, without any change in the relativepositioning or the operating mode of the plunger arrangement. Workers inthe art will perceive this to be a very significant advantage andconvenience.

Workers will perceive other advantage accruing from the foregoing novelhole-encoded flexible disk design according to the invention. One suchadvantage is that it is compatible with the bulk of present dayrecording disk media, as well as with known equipment for handling suchdisks -- thus being adapted, for use, interchangeably, with conventionalfloppy disks where desired. For instance, the existence and pattern ofthe peripheral locator hole pattern need not interfere with, or changein any way, the operation or construction of a conventional(single-disk) drive and Read/Wite assembly. Also, as indicated, the diskis adapted for mounting on standard (single) flexible disk turntablesfor transducing rotation and for relatively conventional transduceraccess and engagement the units being modified to accommodate packdimensions. Further, such an improved flexible disk pack, may becombined with conventional (single-disk) protective jackets, asindicated below and in FIG. 2. Moreover, workers will recognize that a"hole-encoding" scheme such as employed herein for flexible disks may,in certain instances, be adapted for rigid, or semi-rigid disks as well.

Novel disk pack:

According to a principal feature of the invention, improved flexibledisks like those described above are apt for coordination collation andstacking together in combination and properly registered in a novel"flexible disk pack", as indicated, for instance, in FIGS. 4 through 6.It will be evident, of course, that the pattern of locator holes(whether single or double pattern) will be coordinated in the usual casewith a particular stack in mind, the stack being comprised of certainnumber of such disks, with each disk in the stack having its own uniquevariation in the (common) pattern of locator holes e.g. each with aunique number or relative location of holes. Thus, as more fullydescribed below, one may manufacture these disks in sets for efficiencyand convenience sake. For instance, to render a pack such as shown inFIG. 4, one may punch-out a set of "first" (i.e., D-1) disks, then a setof "second" (D-2) disks and so fourth; the disk packs being eachassembled thereafter by collating one each from the D-1, D-2, D-3, etc.,sets, up to a prescribed total number (D-n) in the pack. As a feature ofconvenience the disk total may be left somewhat "open-ended" andvariable, so that disks may be added at any time after a pack is firstassembled.

Manufacturers will find it particularly convenient to manufactureflexible disks according to the invention by relatively convenientinexpensive means, such as in a cutting-out or stamping operation asdetailed below. For instance, for embodiments as in FIG. 4, a die pressarrangement of the type known for working with such polymer sheets maybe made up to cut the "D-1" disk pattern; then it may be modified veryslightly to cut the "D-2" disk pattern, then modified again for the"D-3" disk pattern, etc. (see Ex. 1 below). Alternatively, in the caseof the "double set" of locator holes described above, a similar, butmodified, convenient mode of disk fabrication may be followed. Or, whena single hole pattern is used, only one such die press, and relatedstamping operation, is needed.

Preferably, and according to another feature, when such a disk pack isassembled, the disks are bonded to one another at bond sites dispensedalong a common registering circumference, adjacent the disk center, andspaced radially therefrom to lie in the inner "non-recording" band.Thus, a circular array of "epoxy pillars" B-L is indicated as thebonding sites in FIGS. 3 and 5, to constitute such a pack bonding means,whereby each pillar B (FIG. 5) is comprised of epoxy. This epoxy isintroduced in a viscous liquid form to fill a number of particularregistering sets of bores, one bore through each disk constituting aset. Once the stack has been assembled, with the disks positioned sothat their corresponding apertures and bores lie in registry, suchbond-fillings may be applied together. The viscous epoxy fill, in theusual case, spreads down the bore tunnel and somewhat beyond theperiphery of each bore, to lodge between superposed disks and thenharden to form a clamping "pillar". This "adhesive pillar" will hold thedisks together as assembled in the stack and keep them from lifting awayfrom one another and from being rotated into mis-registration with oneanother.

Workers will contemplate alternate bonding techniques. For instance, onemight interpose an annular spacer between disks in a pack and provide itwith adhesive surfaces adapted to adhere to the upper and lower diskthereby bonding them together. In another technique, where contemplateddisk format and handling allow, one might insert pins through each setof bonding bores and cap their ends, thus preventing misalignment in theradial and circumferential sense (also, perhaps, allowing prescribedaxial freedom to better accommodate pack partitioning).

Workers in the art will recognize that such a permanently bondedflexible disk pack is new in the art and is uniquely well adapted formany desirable functions, such as the hole-encoded disk selectionoperations (described elsewhere), as well as for containment andoperation of the pack -- as a whole -- within a protective jacket (asdescribed below). Thus, workers may now contemplate the use of amultidisk flexible pack as a multi-surface unit record which is almostas lightweight, as compact and as easy to manipulate, store, transport,etc. as a single disk, while having many times its storage capacity.

By way of illustration, it has been found that a pack of 20 flexibledisks according to the invention (e.g., as in FIG. 3 and Table I), eachwith a nominal 3 mil thickness, can be used in a "floppy disk pack"presenting a composite thickness of little more than 60 mils and, rathersurprisingly, may be readily packaged and operated in a protectivejacket similar to the prior art jacket indicated in FIG. 2. Further,such a pack may be manipulated and operated inside this jacket with diskdrive equipment that requires relatively little modification over theconventional single-disk drives known in the art.

--Liners:

FIG. 5A indicates a similar pack of flexible disks, D-1 through D-n,understood as bonded together in fixed, registering superposition toform a single unitary multi-disk pack ST. This pack is, however,somewhat modified, according to a further improvement feature, toinclude protective flexible spacers, or "liners" (SL) interleavedbetween adjacent disks in the pack. More particularly, FIG. 5A shows theupper two flexible disks, D-1 and D-2, exploded away from stack ST forillustrative purposes, and indicates the protective liner means in theform of flexible plastic disks, SL-1 and SL-2, interposed betweenD-1/D-2 and between D-2/D-3, respectively.

Preferably (and mostly for convenience), liners SL are comprised of thesame (or a closely similar) flexible plastic material as the disksubstrates, but of course, will preferably carry no magnetic coating. Ithas been found that confronting oxide-coated sheets in certainembodiments may be rubbed or scraped against one another such as to"scour" or gall magnetic oxide from one to the other. For instance, thismay occur with a novel flexible disk pack during partitioning, etc., andcan be damaging.

According to this feature, liners S may be provided to protect everyoxide surface, preferably being bonded together along with the disksinto a unitary pack. Liners SL include an index hole I-h in registrywith that of the disks D, as well as a locator hole pattern identicalwith that of the adjacent disk and in registry therewith. As to the"up-holes" (e.g., L-1U illustrated in SL-1 -- i.e., adapted for the "up"select/partitioning arrangement represented by the disk embodiment inFIG. 3), it will be understood that a liner's locator hole pattern willbe identical to that of its adjacent superposed disk (here disk D-2 forliner SL-2, D-1 for SL-1). For embodiments also including "down-holes"(as in the embodiment of FIG.3B) the down-hole pattern of a liner willfollow that of its infraposed disk (so a liner will never intervenebetween a transducer and exposed disk). Thus, the spacers, or liners SL,may for instance, comprise a clear polyester, such as polyethyleneterephthalate (e.g., a white "Melanex", trade name of ICI) about 1-2mils thick, or a similar thin flexible material with a low friction,"non-galling", anti-wear surface (or surface coating). Liners will beespecially useful where contemplated pack life/usage is to be extendedand the associated pack enlargement can be tolerated.

Alternate liner materials may of course be used as contemplated byworkers in the art, the thickness and other characteristics thereofbeing modified to suit the requirements of a particular application.While not necessary in every application the use of such liners ispreferred in cases where one or both magnetic recording surfaces of aflexible disk, so bonded into a flexible disk pack, exhibit wear andabrasion problems.

Of course, alternative to using liners SL, the stacked disks D may haveone side thereof coated with a protective film, shielding it from suchadverse contact with a facing magnetic recording surface (e.g., acoating of one of several mils of clear plastic such as "Black Watch" by3M Co.) or the plastic substrate may be left uncoated by any magneticoxide or by any similar coating. Of course, as workers in the art know,flexible disk manufacturers to coat both disk sides with a magneticoxide for their own manufacturing convenience, and to prevent curl.

Example 1: Manufacture of Hole-Encoded Flexible Disks:

Workers in this art will visualize various practical ways in whichhole-encoded flexible disk records of the type described may bemanufactured. One such method is schematically indicated in FIGS. 13 and14 and involves a die press, or punch, arrangement particularly apt forpunching-out all the several apertures of disk embodiments like thosedescribed in FIG. 4, etc. above. By way of example and according to anassociated feature, it will be seen that such a disk manufacturingarrangement is intended to punch-out a "family" of related flexibledisks (like disk embodiment D-1, D-2, D-3, etc., in FIG. 4) adapted forcoordinate assembly and operation in a bonded pack like that described,using relatively conventional means and methods.

According to a further feature, this stamping arrangement may also bereadily modified, by means well known in the art, to inexpensively andconveniently manufacture all the different successive-numbered disks ina pack -- each with its unique modification of the select-hole pattern,using, essentially, a single press with simple die modifications. Forinstance, one may, according to this feature, manufacture 1,000identical hole-encoded packs, each comprised of eleven differentflexible disks (D-1 through D-11) by first using the arrangement topress out 1,000 identical "first" disks (D-1); then, with a slightmodification (described below and using the same process) manufacture1,000 D-2 disks, then with a further slight modification manufacture1,000 D-3 disks, etc. -- through D-11. Thereafter, 1,000 packs may becollated and bonded from these.

Accordingly, it will be readily understood that if one starts with acircular disk design having the standard outline configuration (i.e., ofdisk 1 in FIG. 3), this stamping operation will basically function topunch holes of the proper dimension and location for the spindle, forthe index hole, for the bonding apertures, and for the selected patternof locator holes -- these last being variable according to the disknumber, or hierarchy, in the contemplated pack of FIG. 4. Also, the diskperiphery might then be cut also.

Thus, for example, a flexible sheet of polyethylene terephthalate about3 mils in (nominal) thickness, and having the mentioned circularconfiguration (e.g., diameter of about 14 inches) may be disposed withina concave, cuplike bottom die member D-B, held in a press fixture to beimpressed by a mating press member D-A, adapted to impress the sheetonto D-B and cut out all apertures in one pressing stroke. Thus, pressplate D-A is adapted to be superposed atop a plastic disk so located inD-B and be pressed downwardly by suitable pressing means (known in theart and not shown, but indicated schematically in FIG. 13 at press P),to thereby form the indicated pattern of apertures, punching-out theappropriate segments of this plastic sheet (note the shards SHindicating this in FIG. 13). Except as otherwise described hereinafter,this operation will be understood as being conducted as known by workersin the art from work with similar conventional methods.

More particularly, the cuplike die D-B, understood as the "female die",is provided with apertures of the appropriate size and location; namelyapertures for: the spindle hole 143', and for the (entire, 11-hole)pattern of locator holes 141', these apertures in die D-B being adaptedto receive and mate with corresponding registered protuberances on therelated "male" press die D-A, selectively (when such are present), so asto cut out portions of the plastic disk and thus form the mentioned diskapertures.

Thus, die-press D-A is correspondingly formed with projecting plugs, orpressing protuberance members, understood as, each, adapted to interfit"cuttingly" with an associated congruent one of the mentioned aperturesin die D-B, being of the same relative cross-sectional size andoccupying the same position. Disk D-B thus comprises a spindle plug 143,and index plug 144, an array of bonding points or plugs 142, and avariable array of "selectively removable" locator plugs P.

Locator plugs P are, as schematically indicated in FIG. 14, to beunderstood as, preferably and according to an improvement feature,selectively insertable into a receiving bore and held there for a givenpressing operation -- being apt for removal thereafter, at will, to formany desired variation in the locator hole pattern. Thus, for instance,die-press D-A will be understood in FIG. 14 as illustratively indicatingthe insertion of three locator plugs 145 (i.e., plugs P-1, P-2, P-3)into receiving bores positioned and dimensioned to make the cuts forminglocator holes L-1, L-2 and L-3 respectively in disk 1 in FIG. 3 (alongwith the other associated holes for indexing spindle and bonding, asbefore indicated). These plugs may be held in these bores by suitablemeans (not shown) or may constitute any other like arrangement (known inthe art but not illustrated).

Workers in the art can readily visualize that, in any given pressingrun, one, or several, circular plastic disks may be so impressed to beformed with the pattern of apertures represented by die-press D-A andthat this die-press may thereafter be modified by addition, or removal,of locator plugs 145 to press-out another disk which is identical exceptfor a modified locator hole pattern. For instance, after pressing of asuitable number of D-3 disks with the arrangement of locator plugs 145indicated in FIG. 14, another locator plug P-4 (not shown) may be addedto stamp out "D-4" disks, etc. Of course, the "lower order" disks D-1and D-2 may be formed by removing P-3 and then also P-2 respectively.Thus, it should be apparent to workers skilled in the art that accordingto this feature, with this or any similar stamping operation, stacks ofhole-encoded disks of the type described may be very inexpensively andconveniently produced.

--Associated jacket embodiment:

Novel disk pack embodiments like those above described will beunderstood by workers to be particularly apt for advantageous use in theform of a cartridge, i.e., the resulting structure obtained when thedisk pack is employed in conjunction with a protective jacket structurein which the disk pack remains during partitioning and transducingoperations. Such a jacket 21 is indicated, for instance, in FIGS. 7 and8, being designed somewhat along the lines of a prior art, single-diskjacket 3' (FIG. 2), but modified for the purposes of the presentinvention as illustrated in FIGS. 7 and 8. Jacket 21 is shown in plan"bottom" view in FIG. 7; and is shown, in "top" perspective view, inFIG. 8 as cooperated with jacket-opening means, schematically shown inconjunction therewith and functioning as described below. Such amodified jacket will be perceived as especially suited for housing arotatable pack of flexible disks, like pack S in FIG. 5, being apt foraccommodating the rotation thereof, in situ, as well as for the locatorhole partitioning mode and associated transducer access described above.

Thus, referring to FIGS. 7 and 8, jacket 21 comprises a pair of opposed,relatively flexible panels, namely top panel 21-T and bottom panel 21-B,joined together, along a closed end as well as along about one-half ofthe two adjacent sides by means of flaps f-1, f-2 and f-3 shownextending in partly assembled fashion from top 21-T in FIG. 8, and shownfolded-over and joined to the edges of top panel 21-T in FIG. 7. Panels21-T, 21-B may be comprised of PVC (polyvinyl chloride of about 10 milsnominal thickness), or like material, known to workers in the art.

It will thus be understood that these top and bottom jacket panels 21-Tand 21-B are preferably joined by folding over flaps f-1, f-2 and f-3 soas to permit their being spaced apart sufficiently to form an entry slot21-O for admitting and operating a flexible disk pack of prescribeddiameter and thickness, such as shown in FIG. 5. Jacket 21 will haveconventional apertures corresponding to the spindle hub and index hole(21-H, 21-I, respectively, but slightly enlarged therefrom), as well ashaving two pairs of "spreading-rod apertures" (up-spreader-apertures 22through base panel 21-B, and "down-spreader apertures" 23 through toppanel 21-T), to accommodate the upper and lower jacket spreading means,according to the invention (see in phantom FIG. 8). Illustrative pack Sis shown outlined in phantom in FIG. 7. Spreading is preferably doneautomatically when the so-formed cartridge (jacket 21 containing diskpack S) is inserted into a disk drive, (FIGS. 9 and 10) this beingindicated schematically by the up-thrusting plungers 31 and thedown-thrusting plungers 33 in FIG. 8, according to another feature.Down-plungers 33 are preferably also arranged to pin the jacket to afixed portion of the chassis to hold it fixed with respect thereto whenthe pack is rotated therein. Preferably the "spreading action" of theseplungers is automatically invoked by closing of the entry door of thedrive apparatus after admission of the pack-containing jacket (FIG. 9).It will thus be apparent that the two opposed (upper and lower)"spreader means" 31 and 33 act in concert to separate the outer edges ofthe "entry slot" 21-O when the disk pack is to be "accessed" by atransducer assembly (FIG. 6).

Retainer means such as tabs 24 are also preferably provided withinjacket 21 to retain the disk pack, removably, in prescribed positiontherewithin. These retainer tabs 24 preferably comprise a suitablenumber of upper and lower inwardly-projecting members projectingnormally inward from the top and/or bottom panels adjacent entry-slotS-O and "following" the periphery of the pack as positioned withinjacket 21. This is indicated schematically in FIGS. 7 and 8.

An "entry flap" 21-F is formed of the "outer-half" of top panel 21-T, asschematically indicated in FIG. 8. Flap 21-F is adapted to be pivotedaway from lower panel 21-B, along a prescribed flexing axis F-A_(X) soas to provide an entry slot 21-O sufficient to accommodate thepartitioning of the pack within the jacket as well as the related entryof the transducer assembly, as illustrated in FIG. 6. Preferably, thispivoting flap 21-F is held closed, to retain and protect the containeddisk pack by suitable "spring return" means, either in the form of panelmaterial which is suitably stiff and/or with a stiffening "return-wire"21-W embedded along the periphery of the flap as indicated schematicallyin FIGS. 7 and 8. In extreme cases, return springs may be providedacross slot 21-O.

Jacket 21 also has a slot 21-SL in base panel 21-B to accommodateengagement of the enclosed flexible disk pack (specifically the "bottom"disk thereof) with a transducer "contact pad" (CP) (see FIG. 6) when aRead/Write head is impressed upon (one or several disks in) the pack,opposingly, as known in the art. Similarly, bottom panel 21-B is alsoprovided with an elliptical locator aperture 21-LL adapted for admittinga select-partitioning plunger of the type described above andillustrated in FIG. 5 and elsewhere.

Jacket 21 and the flexible disk pack contained therein thus comprise anovel flexible disk cartridge, with the pack so positioned and heldtherewithin as to be free to rotate, as well as to be selectivelypartitioned and accessed therein as previously described. Jacket 21 ispreferably lined with a non-shedding, non-abrasive cleansing tissue onits inner faces as known in the art, to wipe clean and protect the outersurfaces of the disk pack contacted thereby.

--Modified drive for flexible disk pack:

FIGS. 9 and 10 show a relatively conventional type of flexible diskdrive 100 which has been modified to accommodate operation with novelcartridges (jacketed flexible disk packs) according to the invention.That is, drive unit 100 will be understood by workers in the art tocomprise a compact, portable, disk drive device that interfaces with acentral processor portion of a data processing system by way of asuitable control unit (not shown), as known in the art.

Thus, such a modified disk drive as shown in FIGS. 9 and 11, whileotherwise constructed and operating as known in the art, will beunderstood to include modifications required in order to makeadvantageous use of the novel disk pack and jacket of the presentinvention, such as, for example: jacket-opening spreading means (FIGS.7, 8 and 12); pack rotation (vs. disk rotation) means (FIG. 6); packpartitioning means (FIGS. 3, 6 and 11) and an associated transducerassembly (FIG. 6). The pack-rotating spindle will be understood as beingcontrolled to rotate the pack to any one of several angular orientations(one associated with the accessing of each disk in the pack) forpartitioning, and is preferably operated with a motor adapted to bestepped by prescribed precise constant increments, representing digitalcontrol signals. This facilitates precise digital control to step thepack by precise angular increments to any selected portion orientation.

The jacket or cartridge J (identified by numeral 21 in FIGS. 7 and 8) isadapted for insertion into unit 100, as indicated in FIG. 9, through apivotable "access door" 110 to be thrust in prescribed alignment along aprescribed reference plane defined by left and right side guideways105-R, 105-L, and forward working platform segments 125, 125', 125" tobe positioned against stops 100-S, 100-S' (FIG. 10). With jacket J thusdisposed in "working position", an extended contact pad 117 will beregistered with jacket slot J-S and the disk pack S within the jacketwill be positioned so that its inner contact zone may be engaged forrotation between a lower rotatable spindle 109-A and an upperexpansible-cone, or hub 109 (FIG. 10) adapted to be driven in idlerfashion by spindle 109-A when clamped down on the pack, fitting into thehollow center of spindle 109-A, as well known in the art. Hub 109 (FIG.10) is freely rotatable and is suspended on a clamp arm 107 of apivotable subassembly 136 so as to be pivotable into engagingrotary-driven relation with the so-injected pack holding it on spindle109-A. This engagement is preferably automatically invoked upon theclosing of door 110 as known in the art, with a drive motor 121 beingstarted and coupled (e.g., through a belt drive, etc.) to rotate spindle109-A at "transducing speed" (for example 360 rpm i.e. a "Low-Speed "drive).

The major components of drive unit 100 thus comprise a transduceraccessing arrangement 115, (e.g., including transducer carriage 117 andtranslation motor 111 of FIG. 6), a pack-partitioning subassembly 140including plunger P projectable through a bore in surface 125 (see FIG.11), a jacket-spreading subassembly 150 including two pairs ofup-plungers 31-A /31-B and 33-A/33-B (FIGS. 9 and 10) projectablethrough bores in surfaces 125', 125", (see also FIG. 12), and thementioned rotary drive subassembly 120 (comprising spindle motor 121,spindle 109-A and hub 109 mounted on pivot-arm 107), the entireassemblage being mounted upon a chassis 103. These mechanisms will beunderstood as constructed and operated in a known fashion except asotherwise described.

Thus, transducer subassembly 115 comprises a Read/Write head unit, ormount 117, normally disposed just beyond the pack and adapted to beprojected inward as discussed re FIG. 6, atop a hollow threaded tube 118threadingly engaged on a lead screw 112 adapted to be rotated endlesslyin precise incremental fashion by an associated stepping motor 111. Oncea pack is partitioned, this subassembly will be understood as operativeto translate R/W transducer 15 onto the selected disk surface and trackwith shroud 13 serving to support the upper pack, guiding it over head15 while the pack is rotated.

Access door 110 is preferably mechanically linked to the disk loadingmechanism, including pivoting arm 107 and to a head/load interlockswitch, so that when the door is closed, the pack-rotating spindle-hubis automatically engaged with the pack and the drive subassemblypre-disposed for rotation thereof.

The basic functions of drive unit 100 will be recognized as to receiveand generate control signals, to spread the jacket and partition thepack (disk selection), to position the Read/Write head on selectedtracks of the selected flexible disk and to perform transducingoperations (e.g., write or read data) upon command from the dataprocessing controller. As workers in the art well know, positioning ofthe Read/Write head 15 (FIG. 6) is accomplished conventionally with thelead screw drive from linear stepping motor 111, with head 15 (mountedon the carriage coupled to be translated by this lead screw) stepped-inor -out, upon command, in incremental fashion by actuation of thestepper motor, rotating the lead screw a corresponding amount.

Partitioning is effected, preferably, by a prescribed partitionsubassembly 140 including a select plunger (see plunger P in FIGS. 6 and11) disposed to be thrust upward through an accommodating aperture 123in working surface 125, upon actuation by an associated solenoid SOL.That is, as will be understood from FIG. 11, a "partition-signal"applied to energize the solenoid coil will act to pull a "clapper arm"A-1 down (against return spring 25) and throw an associatedplunger-linkage (arms A-2, A-3 pivotably mounted at pivot pv on thechassis) downward and thereby thrust plunger P upward as indicated inphantom in FIG. 11. This partition assembly will be recognized asparticularly compatible with the subject "floppy pack" and with unit 100to perform the select partitioning function of the jacket-encapsulatedpack in the above indicated manner.

According to a related feature, spindle drive motor 121 is adapted torotate the pack, disposed within the jacket J and engaged between hub109 and drive spindle 109-A, for transducing, as known in the art, aswell as to shift according to a related improvement feature, into asecond rotary-step mode for partition-positioning. That is, responsiveto a prescribed indexing (digital) control signal, motor 121 willdigitally step the spindle and pack rotationally by a prescribed precisenumber of integral angular increments until the selected "partitionorientation" (i.e. rotation) is achieved. Thus, in effect, the pack ismade to step from "zero" (or "Start Radius" see index hole 1-Ih and axisA_(X) -1, FIG. 3) a prescribed number of "angular steps" to thereby"count" its way, digitally, to a prescribed locator hole position. Here,a plunger P may thrust the pack to partition it and expose thecorresponding selected disk recording surface, as described above. Forinstance, in this embodiment it is convenient to step-rotate the pack1.8° per digital "stepping pulse" using a dual mode motor, so that, withthe locator holes (embodiment of FIG. 3) separated at 18° intervals,each rotary increment of 10 steps will carry the pack 18°, i.e., fromone locator hole to the next.

Thereupon the transducer carriage means (see --step tranlation motor111) may be activated to initiate head entry into the so-partitionedpack (from an outer reference position) while the partitioning plunger Pis conjunctively withdrawn. Carriage-entry will thrust the transducerdown upon the selected disk surface and will allow the distal end of thetransducer mount, and particularly shroud 13 mounted thereon, to contactand assume support of the upwardly-thrust portion of the pack. Shroud 13will maintain this contact, guidingly, while the pack is rotated and theRead/Write operations are performed.

That is, stepping motor 111 will translate the transducer head into thesplit pack and place it in compliant "gliding" contact with the selectedrecording surface of the disk for transducer operation (e.g., see U.S.Pat. No. 3,810,243 for typical operations). Upon completion of thetransducing operations, at one or several tracks, the head may bewithdrawn and a different recording surface (disk) accessed in anotherpartitioning cycle. The indicated novel partitioning and head mountarrangements will be seen as establishing stable, protected transducerpositioning at any selected disk surface of such a flexible pack.

According to this feature, the transducer is kept disk-engaged whilemoving from track to track on the selected recording surface, until itis entirely disengaged and withdrawn to the outer "rest position" (FIG.6). During partitioning and transducer entry, the rotary drive will, ofcourse, hold the pack in fixed position, being thereafter rotated (at360 rpm) for transducer operation with the "upper" deflected disks(above the selected one) being bent smoothly up over the mentionedshroud 13, as they pass over the transducer carriage 117.

Shroud 13 is configured, positioned and adapted, according to a relatedfeature, to smoothly, frictionlessly guide and urge these "upper disks"(above the split) thus upward, while they are so rotated to permit theunimpeded, non-damaging entry and withdrawal of the transducer mountinto, and out of, the split-pack (e.g., for Read/Write operations atdifferent disk tracks).

Workers in the art will appreciate that with such a select/partitioningmeans, operable in conjunction with such a hole-encoded flexible diskpack, the pack may be split to expose any selected disk, conveniently,yet precisely -- e.g., simply rotating the pack to a prescribed angularposition corresponding with registry of the plunger with the associatedpartitioning pattern of locator-holes, then thrusting the plunger upthese locator-holes sufficient to admit entry of the transducer-shroud.Thereupon the plungers are retracted and rotation of the pack may beresumed.

Thus, for instance, when the "nth" disk in a pack is selected, the packwill be rotated to "START" position (index hole reference), then steppedby (n × 18°) the angular increments corresponding with a rotation of thepack so that the associated locator-sites register with theplunger-locus. Up-thrust of the plunger will then lift all disks "aboven" away from the upper surface of "n" disk, exposing the latter fortranducer entry as described. For instance, as workers know, such astepping motor/lead screw arrangement can position the transducer headon any one of about 77 discrete track positions of a disk surface.Unexpectedly the "paper thin" disks can interfit slidingly whilerotating, yet appear to experience minimal frictional wear and damage atthe contacting surfaces, especially when protected by the mentionedflexible inter-liner means.

--Jacket spreading:

Drive unit 100 is provided with a jacket-opening and spreadingarrangement 130 (FIGS. 9, 10 and 12) which essentially comprises a pairof upward-thrusting plungers 31-A and 31-B and a related opposed pair ofdownward-thrusting plungers 33-A and 33-B (see also FIG. 8) coupled topivotable subassembly 136 so as to provide for functioning in theaforeindicated manner to automatically spread the entry slot edges ofjacket J (i.e., raise flap 21-T as indicated in phantom 21-T' and 31' inFIG. 12) to accommodate the partitioning of the pack inside and theentry of the transducer carriage 117 (FIGS. 9 and 10). As mentionedpreviously in connection with FIG. 8, the downward-thrusting plungers 33serve to pin the lower panel 21-B against forward guide platforms 125"and 125' to thereby hold the jacket fixed when the disk pack is rotatedwithin the jacket.

--Conclusion:

In summary, workers in the art will recognize that the foregoingdescribed embodiments are well adapted to provide novel, unobviousimprovements in multi-disk media, as well as associated manufacturingmethods -- especially for flexible disks -- plus protective jacket meansand disk handling means including jacket spreaders and pack-partitioningarrangements according to the invention. Workers will also recognizethat, while a particular disk handling embodiment has been described,for clarity, the subject novel flexible cartridges (i.e., novel diskpacks and associated jacket) are entirely feasible for use with otherdisk handling arrangements, especially where these include the same orsimilar jacket spreading and pack-partitioning means. For instance,workers will recognize that, instead of the described partitioning meansoperating about the circumferential periphery of the disk pack, a likearrangement may be provided to operate closer to the center of the packsuch as upon like encoded holes arranged about an inner disk track.

That is, a series of hole-encoded collars may be substituted (nohole-encoding of disks), each supporting a respective disk in a pack andremovably coupled (e.g., by key-way means) to a common hub, or spindle,with a similar plunger means being arranged to be thrust up through thisstack of collars and deflect (upward) those "above" a given selecteddisk. Such an arrangement may be more apt for rigid disks.

Moreover, whereas the illustrative partitioning and/or jacket openingmeans are mechanical, it will be apparent that alternate means such aspneumatic or hydraulic partitioning means will in certain cases alsoserve. For instance, one could substitute a gas injection tube for themechanical plunger of the indicated partitioning arrangement and propela burst of pressurized gas up through a selected registered group oflocator-holes, as understood and appreciated by workers, under propercircumstances to (at least partially) partition the pack sufficient toallow transducer entry -- in certain cases this will even reduceassociated abrasion and defacement of disk surfaces as well asaccelerate partitioning. One can introduce pressurized gas from inside aspindle hub adjacent the partitioning plane so that in case the disksare not rigid enough at their periphery once their hubs are raised tothe reference plane, application of a stream of pressurized gas can thenproceed radially out to maintain them raised. Then, once the head entersand the turntable begins to spin, much less gas pressure would probablybe required to maintain them in position above the partitioning plane asdesired, and certainly in conjunction with a supporting shroud. Further,in certain cases partitioning may be effected without completelyarresting the rotating disk pack (e.g., while quickly incrementing thepack in digital stepped fashion between R/W rotation sequences).Similarly, jacket spreading may be otherwise implemented within thebroad confines of the described concepts, for instance, by lateralintroduction of a pair of relatively horizontal vertically-expandablespreaders disposed relatively along the plane of an injected disk packto be automatically engaged, then expanded, as the jacket is thrust intothe disk drive assembly.

With the preferred embodiments of the invention thus described indetail, those skilled in the art will be able to contemplate certainmodifications in structure and/or method over that illustrated anddescribed, and/or contemplate the substitution of equivalent elementsfor some or all of those disclosed, while nonetheless practicing thenovel concepts described and claimed herein; accordingly, it is intendedthat all such modifications and substitutions be embraced insofar asthey fall within the spirit and scope of the appended claims.

What is claimed is:
 1. A portable partitionable pack of flexible diskscomprising:a plurality of like flexible recording disks, the disks beingformed and arranged in a concentric stack so that the stack is"partitionable end-wise" rather than from the side; each said disk ofsaid stack having a central bore for engaging disk pack rotation meansand an encoded arrangement of "partition apertures" provided about atleast part of a common arcuate segment relatively concentric with thedisk center; the disks being attached together adjacent this centralbore and being formed and stacked so that these segments register and sothat predetermined, superposed apertures of different disks lie inregistry to thereby generate at least one set of "blind deflectionbores" extending through the stack from one end thereof, each such borein a set terminating at a respective different disk in the stack, so asto accommodate the selective partitioning deflection of said respectivedisk in cooperation with "end-wise partition means" adapted to beselectively thrust along any such bore which has been registered withit.
 2. The invention in accordance with claim 1, wherein means areprovided for bonding said disks together at areas sufficiently close tothe center of the stack to permit it to be flexed-open between aselected pair of adjacent disks in response to a thrusting force appliedthrough a corresponding one of said bores.
 3. The invention inaccordance with claim 1, wherein said apertures are disposed equidistantalong said segment at index sites adjacent a common outer circumferenceabout the disks, with each of said bores thus located at a uniqueangular position about the stack, thereby enabling selectivepartitioning of disks by thrust means thrust up through the stack atappropriate times; with selection being effected simply according towhich bore is registered with this thrust means.
 4. The invention inaccordance with claim 3, wherein said apertures comprise holes spacedalong said common circumference.
 5. The invention in accordance withclaim 4, wherein a unique, different pattern of apertures is formed oneach disk so that stacking the disks with the common index sites incongruence will render said set of bores.
 6. The invention in accordancewith claim 3, wherein said apertures comprise notches, cut-out along theperiphery of the disks, each disk being so arranged in the stack that adifferent pattern of registered notches comprises each said bore, forselective register with the associated partitioning thrust means.